Background Metastatic lesions to the thyroid gland are exceedingly rare with the most common primaries typically being lung, renal and breast cancer. Colorectal cancer (CRC) rarely metastasises to the thyroid with few case reports available describing this. Case Presentation A 52-year-old man with a history of cT4N1M1 CRC was referred to ENT for progressive cervical lymphadenopathy on surveillance CT imaging 4 years after initial diagnosis and treatment with chemoradiotherapy. The patient had noted neck swelling and dysphonia for several months but no dysphagia/odynophagia or dyspnoea. Physical examination revealed a large goitre, palpable firm bilateral cervical lymphadenopathy and decreased mobility of the left vocal cord on flexible nasoendoscopy. CT imaging illustrated extensive cervical lymphadenopathy with diffuse infiltration and enlargement of the thyroid gland. PET imaging showed FDG avidity to this area as well as to the primary rectal site, lymphadenopathy below the diaphragm and hepatic metastasis. US FNA of the thyroid showed morphological features favouring metastatic carcinoma but primary thyroid malignancy could not be excluded as there were inadequate cells for immunohistochemistry. Subsequent core biopsy with immunohistochemistry illustrated that malignant cells were positive for CK20 and negative for CK7 and TTF-1 consistent with metastatic colorectal carcinoma. The patient is undergoing systemic chemotherapy. Discussion/ Conclusion Thyroid metastasis from colorectal carcinoma is very rare and often indicates disseminated disease as seen here. This case illustrates the importance of adequate biopsy and immunohistochemistry testing in differentiating a primary thyroid malignancy from a metastatic lesion, particularly in patients with prior history of malignancy. This will allow for timely diagnosis and individualised management options to be offered to patients depending on their disease and overall state.